Please find below a list of corrections made to this article. The location of the corrections refer to the original PDF version of the article. However, please note that both the PDF and XML versions of the article have since been modified to reflect these changes.

1) An error was made in the definitions of d′ on pages 1, 4 and 9:

On page 1 (3rd sentence of the second column), the authors wrote: “… d′V1–V2 = 0.5(z(Hv1) − z(Hv2)) …” The number 0.5 is a mistake and should be removed with the corresponding parenthesis, i.e. it should read: “ … d′V1–V2 = z(HV1) − z(HV2) …”

On page 4 (3rd sentence of the first column), the authors wrote: “…calculated as d′V1–V2 = (z(HV1) − z(HV2))/2 …” The division by 2 is a mistake and should be removed, i.e. it should read: “…calculated as d′V1–V2 = z(HV1) − z(HV2)…”

On page 9 (23rd sentence from bottom of the first column), the authors wrote: “ … d′ = z(H) − z(FA)/2 …” The division by 2 is a mistake and should be removed, i.e. it should read: “…d′ = z(H) − z(FA) …”

2) First page, second column, first line “The sensitivity d′ … for Vernier Vi” was replaced with the following sentences:

The sensitivity calculations were derived from the standard definition d′ = z(H) − z(FA), where z(H) and z(FA) is the hit rate and the false alarm rate, respectively. The sensitivity between two Verniers V1 and V2 offset to different sides was calculated as d′V1–V2 = z(HV2) + z(HV1) and the sensitivity between two Verniers V1 and V2 offset to the same side was calculated as d′V1–V2 = z(HV2) − z(HV1).

3) Page 3, second column, line 4 from the bottom “The decision criterion can be calculated … z(FAVSL)” was replaced with “The decision criterion can be calculated as c = 0.5(z(H) + z(FA)) as well as c = −z(FAVSL)”.

4) Page 4, first column, line 2 sentence starting with “The sensitivity …” was replaced with the sentence: “The sensitivity between two Verniers V1 and V2 offset to different sides was calculated as d′V1–V2 = z(HV2) + z(HV1) and the sensitivity between two Verniers offset to the same side was calculated as d′V1–V2 = z(HV2) − z(HV1). HV1 and HV2 are the hit rates for the two Verniers V1 and V2.”

5) Two sub figures in Figure 4 had been switched. As a result, a corrected Figure 4 has been uploaded.